BARRE — The Granite City man accused of having sexual contact with two 15-year-olds in separate incidents has been charged with sexually assaulting a 13-year-old girl.

Jonathan Amell, 20, pleaded innocent Thursday in Washington County criminal court to felonious sexual assault on a victim under age 16. If convicted, he faces a maximum of 20 years in prison and a $10,000 fine.

According to the police affidavit, the girl said she, Amell and two friends were all playing hide-and-seek at the Montpelier Recreation Field in October. The girl told police she went into the bathroom and into a stall. Police said she told them Amell then came into the bathroom, crawled under the stall door and forced her to have sex with him.

The girl told police she repeatedly told Amell “no” and to stop, but that he did not and kept saying, “It’s OK.”

When questioned by police, Amell denied having sex with the girl and said she was “like a sister” to him, according to the affidavit.

Amell is already facing charges of having sexual contact with a girl in November 2011. According to the police affidavit in that case, the girl told police Amell forced her to the ground and had sex with her. The girl told police she told Amell “no” a few times, but that Amell repeatedly told the girl he loved her.

Police said that when they questioned Amell, he admitted there was sexual contact between him and the girl but said she had initiated it and that it involved only her hand.

Amell is already facing a sex assault charge from an incident in December. According to the affidavit in that case, Amell and a girl were drinking at Bert Wendel’s house in Middlesex and the girl got “extremely intoxicated.”

The girl said she and Amell went outside for a cigarette and that Amell asked her if she wanted to have sex, according to police. The girl said she turned him down, police said, but the next thing she remembered was walking into the woods and having sex with Amell.

If convicted in those two cases, Amell faces a maximum of 35 years in prison.

Wendel, 47, is facing charges of having a sexual relationship with the girl who had been at his house.